Re: Transformers

To: tesla-at-grendel.objinc-dot-com
Subject: Re: Transformers
From: jim.fosse-at-genie-dot-com
Date: Fri, 9 Feb 96 03:14:00 UTC 0000
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Hi,
        I've got an Atlas Device Corporation 6500W Arc Lamp starter that I
have been trying to determine the output current on. It is a shunt limited
transformer with a core 6.25" long, 3.75" high and 1.25" X 1.25" cross
section. It's name plate rates it a 220v 50A, but the 50A MUST be a surge
rating, nothing inside is that heavy! With 110Vac applied to the primary I
measure 7.28Kv out. I find this reasonalble for a 220v transformer run on
110v.

        Now for the confusing part. When I connect an ampeure meter to the
secondary I measure NO current! Even on the 250uA scale! When I use a load
resistor 1 ohm = 0uV. 250 ohm = 5v => 20ma, 2100 ohm = 43v => 20.5ma. Am I
missing some fact about shunt limited transformers? This transformer is
massive compared to the 30ma neons I've seen. Does halving the input voltage
more than halve the output current? Does the load effect the output current?

The primary measures 20 ohms. The secondary 19K ohms. the lower case "u" in
the above sentances REALLY was micro 10^-6.

                I'm confused.

                jim
 p.s. I've still got my 1800pf 30Kv doorknob across the secondary.

                jim